Geodetic very long baseline interferometry: an overview

Since the inception of the Very Long Baseline Interferometry (VLBI) system in 1967, this radio interferometry technique has revolutionised the fields of geodesy, geodynamics and astrometry. With the unprecedented precision and resolution made possible by VLBI various tasks such as geodetic positioning, reference frames interconnections, Earth rotation and polar motion monitoring, estimating the crustal movements, and mapping the extra-galactic radio sources, have attained accuracies of the levels never reached before. Due to its tremendous potential “to provide important new geodetic, geophysical, and astrometric information” geodetic VLBI “moved from an era of development and demonstration to routine operational activities into a period of refinement, rapid extension, and widespread recognition”. Thus, VLBI is the most precise Geodetic technique available today, with numerous applications in different fields.